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	/*
	* Copyright (c) 2017, 2021, Oracle and/or its affiliates. All rights reserved.
	*/
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package com.sun.org.apache.bcel.internal.generic;

	import java.io.DataOutputStream;
	import java.io.IOException;

	import com.sun.org.apache.bcel.internal.util.ByteSequence;

	/**
	* Select - Abstract super class for LOOKUPSWITCH and TABLESWITCH instructions.
	*
	* <p>We use our super's {@code target} property as the default target.
	*
	* @see LOOKUPSWITCH
	* @see TABLESWITCH
	* @see InstructionList
	* @LastModified: May 2021
	*/
	public abstract class Select extends BranchInstruction implements VariableLengthInstruction,
	StackConsumer /* @since 6.0 */, StackProducer {

	private int[] match; // matches, i.e., case 1: ... TODO could be package-protected?
	private int[] indices; // target offsets TODO could be package-protected?
	private InstructionHandle[] targets; // target objects in instruction list TODO could be package-protected?
	private int fixed_length; // fixed length defined by subclasses TODO could be package-protected?
	private int match_length; // number of cases TODO could be package-protected?
	private int padding = 0; // number of pad bytes for alignment TODO could be package-protected?

	/**
	* Empty constructor needed for Instruction.readInstruction.
	* Not to be used otherwise.
	*/
	Select() {
	}


	/**
	* (Match, target) pairs for switch.
	* `Match' and `targets' must have the same length of course.
	*
	* @param match array of matching values
	* @param targets instruction targets
	* @param defaultTarget default instruction target
	*/
	Select(final short opcode, final int[] match, final InstructionHandle[] targets, final InstructionHandle defaultTarget) {
	// don't set default target before instuction is built
	super(opcode, null);
	this.match = match;
	this.targets = targets;
	// now it's safe to set default target
	setTarget(defaultTarget);
	for (final InstructionHandle target2 : targets) {
	notifyTarget(null, target2, this);
	}
	if ((match_length = match.length) != targets.length) {
	throw new ClassGenException("Match and target array have not the same length: Match length: " +
	match.length + " Target length: " + targets.length);
	}
	indices = new int[match_length];
	}


	/**
	* Since this is a variable length instruction, it may shift the following
	* instructions which then need to update their position.
	*
	* Called by InstructionList.setPositions when setting the position for every
	* instruction. In the presence of variable length instructions `setPositions'
	* performs multiple passes over the instruction list to calculate the
	* correct (byte) positions and offsets by calling this function.
	*
	* @param offset additional offset caused by preceding (variable length) instructions
	* @param max_offset the maximum offset that may be caused by these instructions
	* @return additional offset caused by possible change of this instruction's length
	*/
	@Override
	protected int updatePosition( final int offset, final int max_offset ) {
	setPosition(getPosition() + offset); // Additional offset caused by preceding SWITCHs, GOTOs, etc.
	final short old_length = (short) super.getLength();
	/* Alignment on 4-byte-boundary, + 1, because of tag byte.
	*/
	padding = (4 - ((getPosition() + 1) % 4)) % 4;
	super.setLength((short) (fixed_length + padding)); // Update length
	return super.getLength() - old_length;
	}


	/**
	* Dump instruction as byte code to stream out.
	* @param out Output stream
	*/
	@Override
	public void dump( final DataOutputStream out ) throws IOException {
	out.writeByte(super.getOpcode());
	for (int i = 0; i < padding; i++) {
	out.writeByte(0);
	}
	super.setIndex(getTargetOffset()); // Write default target offset
	out.writeInt(super.getIndex());
	}


	/**
	* Read needed data (e.g. index) from file.
	*/
	@Override
	protected void initFromFile( final ByteSequence bytes, final boolean wide ) throws IOException {
	padding = (4 - (bytes.getIndex() % 4)) % 4; // Compute number of pad bytes
	for (int i = 0; i < padding; i++) {
	bytes.readByte();
	}
	// Default branch target common for both cases (TABLESWITCH, LOOKUPSWITCH)
	super.setIndex(bytes.readInt());
	}


	/**
	* @return mnemonic for instruction
	*/
	@Override
	public String toString( final boolean verbose ) {
	final StringBuilder buf = new StringBuilder(super.toString(verbose));
	if (verbose) {
	for (int i = 0; i < match_length; i++) {
	String s = "null";
	if (targets[i] != null) {
	s = targets[i].getInstruction().toString();
	}
	buf.append("(").append(match[i]).append(", ").append(s).append(" = {").append(
	indices[i]).append("})");
	}
	} else {
	buf.append(" ...");
	}
	return buf.toString();
	}


	/**
	* Set branch target for `i'th case
	*/
	public void setTarget( final int i, final InstructionHandle target ) { // TODO could be package-protected?
	notifyTarget(targets[i], target, this);
	targets[i] = target;
	}


	/**
	* @param old_ih old target
	* @param new_ih new target
	*/
	@Override
	public void updateTarget( final InstructionHandle old_ih, final InstructionHandle new_ih ) {
	boolean targeted = false;
	if (super.getTarget() == old_ih) {
	targeted = true;
	setTarget(new_ih);
	}
	for (int i = 0; i < targets.length; i++) {
	if (targets[i] == old_ih) {
	targeted = true;
	setTarget(i, new_ih);
	}
	}
	if (!targeted) {
	throw new ClassGenException("Not targeting " + old_ih);
	}
	}


	/**
	* @return true, if ih is target of this instruction
	*/
	@Override
	public boolean containsTarget( final InstructionHandle ih ) {
	if (super.getTarget() == ih) {
	return true;
	}
	for (final InstructionHandle target2 : targets) {
	if (target2 == ih) {
	return true;
	}
	}
	return false;
	}


	@Override
	protected Object clone() throws CloneNotSupportedException {
	final Select copy = (Select) super.clone();
	copy.match = match.clone();
	copy.indices = indices.clone();
	copy.targets = targets.clone();
	return copy;
	}


	/**
	* Inform targets that they're not targeted anymore.
	*/
	@Override
	void dispose() {
	super.dispose();
	for (final InstructionHandle target2 : targets) {
	target2.removeTargeter(this);
	}
	}


	/**
	* @return array of match indices
	*/
	public int[] getMatchs() {
	return match;
	}


	/**
	* @return array of match target offsets
	*/
	public int[] getIndices() {
	return indices;
	}


	/**
	* @return array of match targets
	*/
	public InstructionHandle[] getTargets() {
	return targets;
	}

	/**
	* @return match entry
	* @since 6.0
	*/
	final int getMatch(final int index) {
	return match[index];
	}


	/**
	* @return index entry from indices
	* @since 6.0
	*/
	final int getIndices(final int index) {
	return indices[index];
	}

	/**
	* @return target entry
	* @since 6.0
	*/
	final InstructionHandle getTarget(final int index) {
	return targets[index];
	}


	/**
	* @return the fixed_length
	* @since 6.0
	*/
	final int getFixed_length() {
	return fixed_length;
	}


	/**
	* @param fixed_length the fixed_length to set
	* @since 6.0
	*/
	final void setFixed_length(final int fixed_length) {
	this.fixed_length = fixed_length;
	}


	/**
	* @return the match_length
	* @since 6.0
	*/
	final int getMatch_length() {
	return match_length;
	}


	/**
	* @param match_length the match_length to set
	* @since 6.0
	*/
	final int setMatch_length(final int match_length) {
	this.match_length = match_length;
	return match_length;
	}

	/**
	*
	* @param index
	* @param value
	* @since 6.0
	*/
	final void setMatch(final int index, final int value) {
	match[index] = value;
	}

	/**
	*
	* @param array
	* @since 6.0
	*/
	final void setIndices(final int[] array) {
	indices = array;
	}

	/**
	*
	* @param array
	* @since 6.0
	*/
	final void setMatches(final int[] array) {
	match = array;
	}

	/**
	*
	* @param array
	* @since 6.0
	*/
	final void setTargets(final InstructionHandle[] array) {
	targets = array;
	}

	/**
	*
	* @return the padding
	* @since 6.0
	*/
	final int getPadding() {
	return padding;
	}


	/** @since 6.0 */
	final int setIndices(final int i, final int value) {
	indices[i] = value;
	return value; // Allow use in nested calls
	}
	}

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